Conventionally, a power transmission device for hybrid vehicle, which is described in, for example, Patent Document 1 has been known as a power transmission device for hybrid vehicle which can be driven by an engine and two motors.
For example, a power transmission device for hybrid vehicle 100 according to Patent Document 1 is provided with an engine 101, a first motor 102, and a second motor 103 as described in FIG. 9, wherein the engine 101 is connected directly to the second motor 103, the engine 101, an output shaft 104 from the second motor 103, and a driven shaft 105 are connected to each other via a first clutch 106, and the first motor 102 and the driven shaft 105 are connected to each other via a second clutch 107.
Therefore, when the vehicle is driven by the engine 101, the first motor 102 is prevented from rotating together by connecting the first clutch 106 and disconnecting the second clutch 107. On the contrary, when the vehicle is driven by the first motor 102, the engine 101 and the second motor 103 are prevented from rotating together by disconnecting the first clutch 106 and connecting the second clutch 107.